By Sunday morning, the rain was pounding and our hotel in downtown Houston was running on backup generators.

Rain is in the forecast well into the coming week. The staff said they were prepared to hunker down at the hotel for the next few days, stocked with enough food and water to hopefully last themselves and the guests.

Hurricane Harvey slams into southern Texas

When my camera crew and I pushed off into the rain, we quickly realised how close we were to the flood.

Three blocks from the hotel, the water reached the top of our vehicle’s tires.

As we began to pass abandoned cars to our left and right, we made a hasty retreat.

But our plight was nothing compared to the massive amount of people currently trapped in their homes.

Houston rescue workers responded to more than 1,000 calls for help overnight, turning roads into boat ramps and telling people to get to their roofs.

Later, another 1,000 calls for rescue were waiting to be answered.

City leaders are calling on residents with boats to help their neighbours.

Large trucks normally used for city sanitation have been commandeered to join the overwhelmed rescue fleet.

I asked a wet man walking along the highway where he was going.

He said his car had been flooded and now he was trying to get home to his wife and two children.

The water was to their patio, he said, and he feared in the coming hours his trapped family would be in danger.